Increase in wiring delay in metal wiring with miniaturized multi-layered LSI and 3D memory is a large problem. In order to decrease the wiring delay, it is important to decrease wiring resistance and interwire capacitance. Application of a low-resistance material such as Cu, for example, is put into practical use for decreasing the wiring resistance. However, also in Cu wiring, deterioration in reliability due to stress migration and electromigration, increase in electric resistivity due to a size effect and the like become problematic, so that a low-resistance wiring material excellent in current density tolerance is required.
Application of a carbon-based material such as carbon nanotubes and graphene with excellent physical properties such as high current density tolerance, electric conduction property, thermal conductivity, and mechanical strength attracts attention as a next-generation wiring material expected to be a low-resistance and highly reliable material. Especially, a structure in which the carbon nanotubes is used as longitudinal interlayer wiring and the graphene is used as transverse wiring is being studied.